Air operating cored wire

ABSTRACT

A cored wire electrode for welding in air containing as major core materials Potassium Oxalate K2C2O4; Magnesium Mg; and Manganese Oxide MnO.

United States Patent Nakabayashi Dec. 11, 1973 AIR OPERATING CORED WIRE[56] References Cited [75] Inventor: Masahiro Nakabayashi, BriarcliffUNITED STATES PATENTS Manor, N.Y. 3,177,340 4/1965 Danhien 219/146 [73]Assgnee cm'pmatonNew 3,573,426 4/1971 B1311: e 219/146 3,560,702 2/1971Arikawa et al. 219/146 [22] Filed: July 31', 1972 Primary Examiner-J. V.Truhe [21] App! 2713;, Assistant ExaminerGeorge A. MontanyeAttorney-Paul A. Rose et al. [52] US. Cl 219/146, 117/202, 117/206,

219/137 [57] ABSTRACT 6 n n n 6 a a0; n 6 I n 6 6 6 s l a n a a u I a 66 6 6 l n I u u u I I l4 A 1 5365365"g f 2 major core materialsPotassium Oxalate K,c,0,; Mag- 1 nesium Mg; and Manganese Oxide MnO 7Claims, No Drawings AIR OPERATING CORED WIRE This invention relates toelectric arc welding electrodes and more particularly to a cored wireelectrode for use in electric arc welding in air.

The advantages of a long continuous bare metal electrode containing coreflux material have now become well known, especially for the generalfabrication of mild steel. Electrodes of this type usually containhalides, oxides, deoxidizers and in some cases alloying agents. Whilethis type of electrodes have generally met with success, there is a needto improve the electrode so that the arc created between the electrodeand workpiece is not so harsh or spatter producing.

Accordingly it is the main object of this invention to provide a coredwire electrode which produces a smooth arc with less spatter than thatproduced by prior art electrodes.

Another object is to provide such an electrode that when alloyingagents, such as nickel, are added to the core material, welds havingincreased impact properties over prior art electrodes are obtained.

It has unexpectedly been found that a core wire electrode for use inelectric arc welding in air can be produced which provides on extremelysmooth arc, good slag peeling and improved impact properties in the weldmetal. Such an electrode contains potassium oxalate which acts primarilyas an arc stabilizer and magnesium and manganese oxide. It has beenfound that the ratio of manganese oxide to magnesium should bemaintained between 0.5 to about 2.0 in the flux core material. If themanganese oxide is too high the are becomes unstable and the slag formedbecomes to fluid. If the magnesium content is too high the arc becomesharsh with excessive spatter. When manganese oxide is too low the slaglooses its viscosity and wetting actions is retarded. When magnesium istoo low the are becomes unstable.

Potassium oxalate additions improved arc stability and surprisingly alsoproduced an essentially free feeling slag. It was found that potassiumoxalate must be added in the amount of 0.5 to 2.5 percent weight ofcore.

Another ingredient in the flux core material is magnesium oxide whichacts as a slag former. Other slag formers such as titanium oxide,silicon dioxide or zirconium oxide can be substituted in whole or inpart for the magnesium oxide but in any event the slag former should bepresent in the range of from about 2 to about weight percent of thecore.

Calcium fluoride is also present as a slag former. The amount of calciumfluoride present depends on the amount and type of other slag formerspresent in the flux. For example some of the calcium fluoride may bereplaced with titanium dioxide. However some calcium fluoride must bepresent in order to assist in the wetting action. Preferably the calciumfluoride is present in the range of from 35 to about 70 weight percentof the core. However as noted above the calcium fluoride content may bereduced by substituting some titanium dioxide for example.

Aluminum is present as a deoxidizer and nitride former. Aluminum may bepresent alone or as part of a magnesium-aluminum alloy. However thecritical relationship of magnesium to manganese oxide must bemaintained. It has unexpectedly been found that when the relationship ofmagnesium to manganese oxide is maintained, the manner in which aluminumis added to the flux is not as critical as has been found in other priorart electrodes. Aluminum may be present in the range of from 5 to about20 weight percent of the core.

Also included in the flux core to provide the mechanical propertiesdesired in the weld, is low carbon ferromanganese (FeMn), howevermanganese or different level carbon ferromanganese may be substitutedfor the low carbon ferromanganese. However some manganese must bepresent in order to achieve the mechanical properties. Low carbonferromanganese is preferably used and is preferably in the range of from3 to 9 weight percent of the core.

Nickel is also added to the flux core material in order to achieve highimpact properties. Small additions of nickel expand the gamma loop andreduce growth of dendritic structure in the weld metal. It was foundthat nickel in the range of from 2 to about 5 weight percent of coreproduced the desired impact properties.

A preferred wire A of the invention consists of a mild steel sheathcontaining the following ingredients given in weight percent of thecore.

Aluminum 15.0 CaF, 58.3 MgO 6.0 Potassium Oxalate l.2 MnO 8.5 L.C. FeMn6.0 Magnesium 5.0

The core ratio is 18 percent.

For achieving high impact properties the wire is modifled to consist ofa mild steel sheath containing the following ingredients given in weightpercent of the core.

Aluminum CaF,

Potassium Oxalate MnO L.C. FeMn Magnesium Nickel The core ratio is 18percent. This wire is designated wire B.

Another wire C of the invention was made using aluminum-magnesium alloy.This wire consisted of a mild steel sheath containing the followingingredients given in weight percent of the core with the core being 18percent.

Aluminum CaF,

Fe Powder MgO Potassium Oxalate MnO L.C. FeMn Mg-Al (alloy) (50% Mg) Fepowder was used as a filler to make a compact core because the Mg-Alalloy has a different specific density than aluminum or magnesium powderalone and therefore takes up less space in the core.

Yet another wire D was made using aluminummagnesium alloy with nickeladditions. This wire consisted of a mild steel sheath containing thefollowing ingredients given in weight percent of the core with the corebeing 18 percent.

Aluminum 1.0 Cal", 5 5.0

Fe Powder MgO Potassium Oxalate MnO L.C. FeMn Mg-Al (alloy) (50% Mg) 1Ni Lauryn-Irvin 0000000 Having described the invention in general termsand with reference to certain preferred embodiments the followingexamples are provided to assist one skilled in the art in the practiceof the invention.

EXAMPLE I EXAMPLE II A type B wire containing nickel was .made in threethirty-seconds in. diameter and used to make a multipass weld inthree-fourths inch thick meld steel plate at 350 ampere and 26 voltswith a travel speed of 15 I.P.M.

The mechanical properties were as follows:

89,400 psi U.T.S.; 74,900 psi Y.S.; and impact properties of 25.9 22.5ft./lbs. at F and 19.7-21.0 ft./lbs. at 20 F. This compares with priorart electrodes which usually produce about 67.l ft./lbs. at 0 F and -6ft./lbs. at 20F with a harsh high spatter arc.

EXAMPLE III Wire C was made into three thirty-seconds in. diameter wireand tested as in Example I with the following results:

79,900 psi U.T.S.; 64,600 psi Y.S. and impact properties of 11.2ft./lbs. at 0 F and 6.5 ft./lbs. at 20 F, the arc was smooth and spatterfree.

EXAMPLE IV Wire D was made into three thirty-seconds in. diameter wireand tested as in Example IV with the following results:

98,400 psi U.T.S.: 92,900 psi Y.S. and impact properties of 27.9 26.9ft./lbs. at OF and 21.4 20.5 ft./lbs. at 20F.

It can be concluded from the above that the invention provides anelectrode which produces almost 2 to 3 times the impact properties ofprior art electrodes while producing a smooth low spatter arc. While theexamples illustrate a cored wire having an 18 weight percent core ratioit should be understood marine core may be varied from about 16 to about20 percent. Likewise the diameter of the cored wire may be varied fromthe three thirty-seconds in. diameter illustrated herein.

What is claimed is:

l. A consumable wire electrode for electric arc welding in aircomprising a hollow sheath of mild steel and a flux core comprisedessentially of the following ingredients in core weight percent when thecore is from about 16 to about 18 percent of the total electrode:

Aluminum 5-20 Calcium Fluoride (CaF,) 35-70 Magnesium Oxide (MgO) 2-10Potassium Oxalate 0.5-2.5 z s 4) Manganese Oxide (MnO) 1.5-20 Low CarbonFeMn 3-9% Magnesium 3-10 with the proviso that the ratio of manganeseoxide to magnesium be maintained between 0.5 to about 2.0.

2. A wire according to claim 1 including 2 to 5 core weight percentnickel.

3. A wire according to claim 1 wherein the magnesium is added asmagnesium-aluminum alloy.

4. A consumable wire electrode for electric arc welding in aircomprising a hollow sheath of mild steel and a flux core comprising thefollowing ingredients in core weight percent when the core is 18 percentof the total electrode:

Aluminum MgO Potassium Oxalate MnO 8.5

L.C. FeMn Magnesium 5. A consumable wire electrode for electric arcwelding in air comprising a hollow sheath of mild steel and a flux corecomprising the following ingredients in core weight percent when thecore is 18 percent of the total electrode:

Aluminum CaF,

MgO

Potassium Oxalate MnO L.C. FeMn Nickel 6. A consumable wire electrodefor electric arc welding in air comprising a hollow sheath of mild steeland a flux core comprising the following ingredients in core weightpercent when the core is 18 percent of the total electrode:

Aluminum 1.0 CaF, 55.0 Fe Powder 1 1.0 MgO 5.0 Potassium Oxalate 1.0 MnO7.0 L.C. FeMn 5.0 Mg-Al (all0y)(50% Mg) 15.0

7. A consumable wire electrode for electric arc welding in aircomprising a hollow sheath of mild steel and a flux core comprising thefollowing ingredients in core weight percent when the core is 18 percentof the total electrode:

Aluminum 1.0 CaF, 55.0 Fe Powder 8.0 MgO 5.0 Potassium Oxalate 1.0 MnO7.0 L.C. FeMn 5.0 Mg-Al (alloy) (50% Mg) 15.0 Nickel 3.0

2. A wire according to claim 1 including 2 to 5 core weight percentnickel.
 3. A wire according to claim 1 wherein the magnesium is added asmagnesium-aluminum alloy.
 4. A consumable wire electrode for electricarc welding in air comprising a hollow sheath of mild steel and a fluxcore comprising the following ingredients in core weight percent whenthe core is 18 percent of the total electrode: Aluminum 15.0 CaF2 58.3MgO 6.0 Potassium Oxalate 1.2 MnO 8.5 L.C. FeMn 6.0 Magnesium 5.0
 5. Aconsumable wire electrode for electric arc welding in air comprising ahollow sheath of mild steel and a flux core comprising the followingingredients in core weight percent when the core is 18 percent of thetotal electrode: Aluminum 11.0 CaF2 58.6 MgO 6.0 Potassium Oxalate 1.2MnO 8.5 L.C. FeMn 6.0 Mg 5.0 Nickel 3.7
 6. A consumable wire electrodefor electric arc welding in air comprising a hollow sheath of mild steeland a flux core comprising the following ingredients in core weightpercent when the core is 18 percent of the total electrode: Aluminum 1.0CaF2 55.0 Fe Powder 11.0 MgO 5.0 Potassium Oxalate 1.0 MnO 7.0 L.C. FeMn5.0 Mg-Al (alloy)(50% Mg) 15.0
 7. A consumable wire electrode forelectric arc welding in air comprising a hollow sheath of mild steel anda flux core comprising the following ingredients in core weight percentwhen the core is 18 percent of the total electrode: Aluminum 1.0 CaF255.0 Fe Powder 8.0 MgO 5.0 Potassium Oxalate 1.0 MnO 7.0 L.C. FeMn 5.0Mg-Al (alloy) (50% Mg) 15.0 Nickel 3.0